The scope of efforts to reduce CO2 emissions of vehicles includes advancing the electrification of vehicles, whereby internal combustion engines are intended to be replaced to an increasingly greater extent by electric motors. One of the greatest disadvantages of electrically driven vehicles, however, is that the energy density of stores for electrical energy, such as accumulators, for example, is substantially lower than the energy density of stores that store other energy carriers such as fossil fuels or hydrogen. In order to provide electrically operated vehicles with an acceptable range, the stores for electrical energy is designed to be very large. As a result, not only is a great deal of space needed in the vehicle, which is then no longer available as cargo space, for example, but also the stores for electrical energy have a high dead weight, which results in an increase in the consumption of electrical energy.
Various measures can be taken to keep the stores for electrical energy small and, therefore, lightweight. For example, the hybrid vehicles are equipped not only with an electric motor, but also with an internal combustion engine as well, and so it is possible to use the internal combustion engine or the electric motor for driving the vehicle, depending on the driving state. As a result, both the engine and the motor can be operated largely at their optimal operating points. In city traffic, where frequent accelerations and decelerations are initiated, the electric motor can be operated in a more optimal and, therefore, economical manner than the internal combustion engine, whereas the internal combustion engine can be operated in a more optimal and, therefore, economical manner than the electric motor at high and constant speeds. One disadvantage of hybrid vehicles, however, is that they demand all the components for operating the electric motor and the internal combustion engine, whereby their weight increases and the reduction in weight achieved by reducing the size of the electrical-energy store is at least partially offset by the large number of components. In addition, a complex control system is used to activate either the engine or the motor, whichever may be operated more economically depending on the driving state. The increased number of components and the complex control may increase the likelihood that one or more functions of the hybrid vehicle degrades.
Another possibility for keeping the electrical-energy store small and, therefore, lightweight is to obtain electrical energy directly on the road and introduce it into the electric motor, for example via overhead contact lines or induction elements buried in the ground. The economic impact to equip the road network in this manner is extremely high, however, and so supplying electric motors with electrical energy in this manner is an option only for certain roads. Examples thereof are, in particular, highly traveled roads such as superhighways.
In addition to optimizing the combustion process, the kinetic energy generated during a braking procedure, for example, can be converted into electrical energy and can be fed to the electrical-energy store (recuperative braking). The fuel consumption can therefore be reduced, because the electrical energy does not need to be provided by a generator driven by the internal combustion engine.
Depending on the driving state, however, the situation can occur whereby the electrical-energy store is completely filled, and electrical energy provided by the braking procedure, for example, is otherwise wasted (herein referred to as an energy surplus). In this case, it may be economical to switch on a consumer that is not demanded per se, for example, the rear-window heater, to consume the excess electrical energy which cannot be fed to the store or to entirely dispense with the conversion of kinetic energy into electrical energy. As a result, the kinetic energy remains unused, or the electrical energy is wasted, without having achieved any noteworthy additional benefits. Thus, during the energy surplus, electrical energy that may otherwise be used to power one or more vehicle functions is wasted.
In one example, the issues described above may be addressed by a method for operating the vehicle in a driving state according to instructions of a driver and/or an assistance system, ascertaining the quantity of electrical energy stored in a store of the vehicle via a store-monitoring device, comparing the ascertained quantity of the stored electrical energy with a pre-definable limit value via a control unit, for the case in which the quantity of the electrical energy stored in the vehicle exceeds the pre-definable limit value, feeding a selectable quantity of electrical energy from the vehicle into an external energy-uptake device having an energy-transfer device.
In this way, a ubiquitous network configured to couple to vehicles on a roadway is described. The network and vehicles are in communication when coupled and may determine a direction of energy transfer based on a diagnostic routine. In one example, the vehicle may transfer energy to the network during an energy surplus driving mode (e.g., electrical energy substantially equal to the pre-definable limit value), where an energy storage device is fully charged and engine operating conditions are producing excess energy (e.g., recuperative braking). Alternatively, the network may provide energy to the vehicle in response to the vehicle comprising less than a desired amount of energy (e.g., vehicle does not comprise a sufficient amount of energy to reach a desired final destination determined via a vehicle operator input into a navigation system). In this way, energy from a vehicle may be transferred to and stored in the network, where the network may distribute the stored energy back to the same vehicle or to a different vehicle.
The problem addressed by one embodiment of the present disclosure includes a system for operating a vehicle having an internal combustion engine via which the excess electrical energy that exists during operation of a vehicle comprising an internal combustion engine transferred to other vehicles through a network. In one example, the network is configured to supply electrically driven vehicles with electrical energy, where the network is adapted to receive electrical energy during an energy surplus as described above.
Within the scope of the present disclosure an internal combustion engine is considered to be an engine which burns fossil fuels, for example, as well as hydrogen or other energy carriers (e.g., alcohols, coal, and gas) to provide torque which drives wheels of the vehicle. The internal combustion engine may not be the only drive source for the vehicle. Instead, the vehicle is a hybrid vehicle which comprises an electric motor in addition to the internal combustion engine.
Depending on the configuration of the vehicle, said vehicle can be operated in a certain driving state according to the instructions of a driver and/or an assistance system. The driving state of the vehicle can be characterized, for example, by the instantaneous speed or the time that has passed since the vehicle was started. This also includes operating the vehicle via autonomous driving with the use of the assistance system.
Initially, the quantity of the electrical energy stored in the store (e.g., a state of charge), in particular in the vehicle battery of the vehicle, is continuously ascertained with the aid of the store-monitoring device. The voltage of the stored electrical energy can be measured for this purpose.
Subsequently, it is determined whether the quantity of the electrical energy stored in the store exceeds a pre-definable limit value, or not. This pre-definable limit value defines a reserve which must not be accessed, in order to ensure the safe operation of the vehicle and, in particular, of the electronic components installed in the vehicle. As soon as an actual value drops below the pre-definable limit value, the intended use of the vehicle can no longer be guaranteed for a sufficiently long period of time, for example, until the destination is reached. However, if the quantity of the electrical energy stored in the vehicle exceeds the limit value, then a certain portion of the electrical energy can be delivered and is not demanded for the operation of the vehicle. In this case, a selectable quantity of electrical energy is fed from the vehicle into an external energy-uptake device. The selectable quantity in this case can be an established portion of the difference of the quantity of the stored electrical energy and the limit value, whereby it can be ensured that the quantity of electrical energy delivered is not too high and, therefore, that the reserve is not accessed. The electrical energy is transferred via the energy-transfer device to the external energy-uptake device. The transfer can take place, for example, via induction elements or via a current collector which is brought into contact with a current lead.
In this way, it is possible to feed excess energy that is not needed for the operation of a vehicle comprising an internal combustion engine into an external energy-uptake device, where it can be used in a different way. This can take place, for example, by way of this fed electrical energy being made available to other vehicles that are driven exclusively or partially by an electric motor. The external energy-update device can also contain a storage device, in which the energy can be stored or temporarily stored. This storage or temporary storage can also be implemented via a conversion into another energy-storage form, such as, for example, via a power-to-gas or a power-to-fuel method. Due to the alternate usage of the excess energy that is available during operation of the vehicle comprising an internal combustion engine, it can be ensured that this energy does not need to be uselessly consumed, for example, prevent an overcharging of the electrical-energy store.
In a further embodiment, the method may include determining the quantity of electrical energy that was consumed via a usage meter, and adjusting the quantity of electrical energy fed into the external energy-uptake device via the control unit with consideration for the ascertained quantity of consumed electrical energy via the control unit.
In this case, the quantity of the electrical energy fed into the external energy-uptake device can be dynamically changed by the control unit. In this case, the control unit accounts for the quantity of electrical energy that was consumed, in particular over a certain period of time before the adjustment is carried out. If the control unit establishes that a very large quantity of electrical energy is drawn from consumers of the vehicle, such as the air conditioning system or the rear-window heater, in this time period, the quantity of electrical energy that is fed can be reduced, to prevent the limit value from being quickly reached. For the case in which little electrical energy is drawn from the consumers, the quantity of fed electrical energy can be increased. Therefore, the quantity of fed electrical energy is selected neither too high nor too low. The proper performance of the electrical components of the vehicle is met prior to feeding energy into the external energy-uptake device.
In one alternative embodiment, the store-monitoring device can ascertain the quantity of energy stored in further stores of the vehicle, wherein the quantity of stored energy is taken into account by the control unit. In this case, not only the electrical energy, but also energy stored in other forms is taken into account. The electrical-energy store of a vehicle operated by an internal combustion engine can be charged by way of the internal combustion engine driving a generator. If the fuel tank of the vehicle is well-filled, for example, and it is therefore possible to use a portion of the fuel for charging the electrical-energy store, the electrical-energy store can be discharged to a greater extent than for the case in which the fuel tank is only slightly filled. Alternatively, it is possible to use a portion of the fuel tank in response to a market value of fuel. For example, if the price of fuel is less than the price of electrical energy reserves, then a portion of fuel is consumed to provide energy to the external energy uptake device, thereby allowing a vehicle operator to realize financial gains. In this way, by accounting for the quantity of stored energy, the quantity of electrical energy that can be fed into the external energy-uptake device can be maximized without jeopardizing the proper performance of the vehicle.
In a further embodiment, the method may detect the driving state of the vehicle and generate corresponding driving-state signals using driving-state detection device, and feed the driving-state signals to the control unit which takes the driving-state signals into account when changing the pre-definable value and the fed, selectable quantity.
Driving-state detection device can detect, for example, the speed of the vehicle, and the speed, operating time, and oil temperature of the internal combustion engine. On the basis of these parameters, the future consumption of the internal combustion engine can be forecast. As a result, it is also possible to maximize the quantity of electrical energy that can be delivered. In turn, a greater quantity of electrical energy can be delivered when the consumption by the internal combustion engine is low, since a certain quantity of fuel can be used for charging the electrical-energy store and is not needed for driving the vehicle.
One embodiment is distinguished by the fact that the quantity of consumed electrical energy and/or the driving state with respect to a pre-definable time are/is taken into account. It therefore makes sense to average the quantity of electrical energy that is consumed and the parameters characterizing the driving state, such as speed and engine speed, over a pre-definable time. As a result, short-term outliers, resulting from an acceleration procedure, for example, can be omitted from consideration in the ascertainment of the quantity of electrical energy that can be delivered. As a result, the future consumption by the internal combustion engine may be predicted. In addition, the situation may be prevented, whereby the quantity of electrical energy that can be delivered is changed too frequently.
In a further embodiment, the method may detect the instantaneous position of the vehicle and the planned destination and generate corresponding position and destination signals via a navigation system and feed the position and destination signals to the control unit which takes the position and destination signals into account when changing the pre-definable value and the fed, selectable quantity.
It is not only known how much further away the destination is from the current position of the vehicle, but also what the properties are of the trip segment to the destination. The grades, the number of curves, and the road status of the trip segment are of particular interest. It is also known whether the trip segment extends mainly cross-country or through the city. As a result, it is possible to calculate the fuel consumption of the internal combustion engine until the destination is reached, whereby the quantity of electrical energy that is delivered can be adjusted accordingly.
In another embodiment, the vehicle is operated in such a way that the quantity of energy, in particular fuel, that is consumed is minimized. For this purpose, the internal combustion engine can be operated, for example, at the optimal operating point for as long as possible, which can be achieved in the case of hybrid vehicles, for example, by utilizing the electric motor for acceleration procedures. In addition, the situation can be prevented whereby the internal combustion engine is operated at unfavorable speeds, which can be implemented via a corresponding transmission control and/or by suitable interventions by the assistance system.
In an alternative embodiment, the control unit controls the navigation system in such a way that the route guidance is adjusted as a function of the ascertained quantity of consumed electrical energy and the quantity of energy stored in the store and/or energy stored in the further stores. It can occur that the route guidance originally proposed by the navigation system has been sought out, for example, on the basis of the criterion of reaching the destination within the shortest amount of time. This can mean, however, that the fuel consumption of the internal combustion engine is greater as compared to an alternative route guidance. In order to nonetheless increase the quantity of electrical energy that can be delivered, the navigation system can change the route guidance in such a way that the quantity of consumed energy and, in particular, the fuel consumption of the internal combustion engine are reduced.
In one example, the energy-uptake devices may be located at points, for a certain transition time. If the navigation system then establishes that no energy-uptake devices are present on the originally provided trip segment, but that excess energy that could be delivered is present, the route guidance can be changed in such a way that it passes by one or more energy-uptake devices. The transition time may include installation of the energy-uptake devices along a roadway. Thus, the transition time encompasses a range of time including an absence and a ubiquity of the uptake devices.
In another embodiment, the vehicle is operated in such a way that the quantity of electrical energy consumed is minimized. The less electrical energy needed for operating the vehicle comprising an internal combustion engine, the greater the amount of excess energy that can be delivered. The quantity of consumed electrical energy can be reduced, for example, via a suitable control of the air conditioning system. Depending on the configuration of the vehicle, a corresponding message can be issued to the driver, or the air conditioning system is automatically regulated accordingly.
One embodiment of the present disclosure relates to a system for operating a vehicle comprising an internal combustion engine and, in particular, a system for carrying out a method comprising a store-monitoring device for ascertaining the quantity of electrical energy stored in a store of the vehicle which is operated in a driving state according to instructions from a driver and/or an assistance system, a control unit for comparing the ascertained quantity of the stored electrical energy with a pre-definable limit value, energy-transfer device for feeding a selectable quantity of electrical energy from the vehicle into an external energy-uptake device, wherein the control unit acts, in a controlling manner, on the energy-transfer device in such a way that, in the event that the quantity of electrical energy stored in the vehicle exceeds the pre-definable limit value, the selectable quantity of electrical energy is fed from the vehicle into the external energy-uptake device.
The technical effects and advantages which can be achieved using the system according to the present disclosure correspond to those explained above. In summary, it should be noted that excess energy that is not needed for operating the vehicle comprising an internal combustion engine can be delivered to other vehicles that are operated using an electric motor, so that said energy is not wasted.
One embodiment of the present disclosure relates to a network for supplying electrically driven vehicles with electrical energy, comprising a transfer network for transferring electrical energy, a number of energy-uptake devices, with which electrical energy from one or more vehicles, which comprise an internal combustion engine and are designed, in particular, according to the previously depicted embodiment, can be fed into the transfer network, and a number of energy-exchange devices, via which electrical energy can be exchanged with the vehicles driven by electrical energy. Existing networks, which comprise, for example, overhead contact lines or induction elements for exchanging electrical energy between vehicles, for example, passenger cars, trucks, or trains, and the network, are designed for supplying electrical energy to the vehicles that are operated exclusively using electric motors. According to the present disclosure, it is possible, however, to also integrate vehicles into the network, which comprise an internal combustion engine and are not reliant on drawing electrical energy from the network. The network makes it possible to deliver excess energy that is not demanded for operating the vehicle comprising an internal combustion engine to other vehicles that are operated using an electric motor, so that said energy is not wasted. A contribution is made to the efficient utilization of electrical energy. In addition, the network makes it possible to equip the electrically operated vehicles with an electrical-energy store which is small and, therefore, lightweight. As a result, the consumption of electrical energy is reduced and the available electrical energy is utilized more efficiently.
A further embodiment is distinguished by the fact that the network comprises one or more network stores for electrical energy. The network stores make it possible to also feed electrical energy into the network when a demand for electrical energy does not exist. In addition, electrical energy can also be drawn when electrical energy is not being fed in. The network store therefore has a buffer effect and equalizes differences in the fed-in and withdrawn quantity of electrical energy.
In a further embodiment, the network store contains an energy-converting device which is suitable for carrying out a power-to-gas method or a power-to-fuel method, or is connected to such an energy-converting device, and so the storage can take place in another form of energy.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.